# Thread: cosx and sinx when x= 0

1. ## cosx and sinx when x= 0

why is the value of cos x when x is 0 equal one?:

cos 0= 1

what is the value of sin when x = 0?

are there any other forms of this?

2. Hey there arturdo,

I'm assuming you understand the trig ratios cosine and sine refer to the angular relationship of a right-angled triangle.

Imagine you have a right triangle with a hypotenuse length of 1 unit.

Assume that one corner has angular measure 0 degrees. This means, in reality, the triangle has the appearance of a straight line 1 unit long.

Taking this corner angle of 0 degrees, the cosine ratio can be shown as:

$cos 0^o = \frac {Adjacent}{Hypotenuse} = \frac {1}{1} = 1$

Similarly,

$sin 0^o = \frac {Opposite}{Hypotenuse} = \frac {0}{1} = 0$

Trust this helps.